Change base steps

Author: leomarquine

src/Extractors/Extractor.php

@@ -2,16 +2,14 @@
 
 namespace Marquine\Etl\Extractors;
 
-use IteratorAggregate;
 use Marquine\Etl\Step;
 
-abstract class Extractor extends Step implements IteratorAggregate
+abstract class Extractor extends Step
 {
     /**
-     * Set up the extraction from the given source.
+     * Extract data from an input.
      *
-     * @param  mixed  $source
-     * @return void
+     * @return \Generator
      */
-    abstract public function extract($source);
+    abstract public function extract();
 };

src/Loaders/Loader.php

@@ -7,10 +7,10 @@
 abstract class Loader extends Step
 {
     /**
-     * Get the loader handler.
+     * Load the given row.
      *
-     * @param  mixed  $destination
-     * @return callable
+     * @param  \Marquine\Etl\Row  $row
+     * @return void
      */
-    abstract public function load($destination);
+    abstract public function load($row);
 }

src/Transformers/Transformer.php

@@ -7,9 +7,10 @@
 abstract class Transformer extends Step
 {
     /**
-     * Get the transformer handler.
+     * Transform the given row.
      *
-     * @return callable
+     * @param  \Marquine\Etl\Row  $row
+     * @return void
      */
-    abstract public function transform();
+    abstract public function transform($row);
 }